In the past, designers of avionics systems have endeavored to provide systems with improved functionality and simultaneous cost reductions. One example of an area of inquiry has been the use of holographic optical data storage for storage of large amounts of data to be used in flight systems. For example, recently there has been considerable attention given to reduction of controlled flight into terrain (CFIT). Ground collision avoidance systems have been proposed which use GPS receivers and a terrain database to reduce such CFIT accidents. One obstacle in such systems is providing a terrain database, which contains the vast amount of information required, while concomitantly meeting the needs of very fast data retrieval times. Holographic data storage is one possible scheme that could be used.
While these holographic data storage approaches have many advantages, is they also have significant drawbacks.
Holographic data storage systems require very stable conditions. The relatively short wavelengths of the light in the optical range results in a requirement to preserve precise alignment of components to allow for measurement and detection of these optical signals. However, the environment in an aircraft is relatively hostile. The dramatic temperature changes and vibration, which are commonplace on-board an aircraft, are not trivial obstacles when designing an airborne holographic data storage system.
Use of standard optical laboratory component mounting equipment, such as an optical rail which positions mounting brackets along a linear rail member or an optical table, with numerous mounting holes across the table top, has often failed to provide the requisite preservation of alignment of the optical components.
Consequently, there exists a need for improvement in airborne optical systems which address the requirement of precise alignment of optical components in a relatively hostile environment.